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result(s) for
"Elfring, Gary L."
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Effectiveness of PTC124 treatment of cystic fibrosis caused by nonsense mutations: a prospective phase II trial
2008
In about 10% of patients worldwide and more than 50% of patients in Israel, cystic fibrosis results from nonsense mutations (premature stop codons) in the messenger RNA (mRNA) for the cystic fibrosis transmembrane conductance regulator (CFTR). PTC124 is an orally bioavailable small molecule that is designed to induce ribosomes to selectively read through premature stop codons during mRNA translation, to produce functional CFTR.
This phase II prospective trial recruited adults with cystic fibrosis who had at least one nonsense mutation in the
CFTR gene. Patients were assessed in two 28-day cycles. During the first cycle, patients received PTC124 at 16 mg/kg per day in three doses every day for 14 days, followed by 14 days without treatment; in the second cycle, patients received 40 mg/kg of PTC124 in three doses every day for 14 days, followed by 14 days without treatment. The primary outcome had three components: change in CFTR-mediated total chloride transport; proportion of patients who responded to treatment; and normalisation of chloride transport, as assessed by transepithelial nasal potential difference (PD) at baseline, at the end of each 14-day treatment course, and after 14 days without treatment. The trial was registered with
who.int/ictrp, and with
clinicaltrials.gov, number
NCT00237380.
Transepithelial nasal PD was evaluated in 23 patients in the first cycle and in 21 patients in the second cycle. Mean total chloride transport increased in the first treatment phase, with a change of −7·1 (SD 7·0) mV (p<0·0001), and in the second, with a change of −3·7 (SD 7·3) mV (p=0·032). We recorded a response in total chloride transport (defined as a change in nasal PD of −5 mV or more) in 16 of the 23 patients in the first cycle's treatment phase (p<0·0001) and in eight of the 21 patients in the second cycle (p<0·0001). Total chloride transport entered the normal range for 13 of 23 patients in the first cycle's treatment phase (p=0·0003) and for nine of 21 in the second cycle (p=0·02). Two patients given PTC124 had constipation without intestinal obstruction, and four had mild dysuria. No drug-related serious adverse events were recorded.
In patients with cystic fibrosis who have a premature stop codon in the
CFTR gene, oral administration of PTC124 to suppress nonsense mutations reduces the epithelial electrophysiological abnormalities caused by CFTR dysfunction.
PTC Therapeutics, Cystic Fibrosis Foundation Therapeutics.
Journal Article
Irinotecan plus Fluorouracil and Leucovorin for Metastatic Colorectal Cancer
by
Maroun, Jean A
,
Cox, John V
,
Blanke, Charles
in
Antineoplastic agents
,
Biological and medical sciences
,
Chemotherapy
2000
The antimetabolite fluorouracil is widely used to treat metastatic colorectal cancer, the second-leading cause of death from cancer in North America.
1
The drug inhibits thymidylate synthase, an enzyme required for the synthesis of DNA.
2
It is commonly administered with leucovorin, a reduced folate (tetrahydrofolate) that increases the affinity of fluorouracil for thymidylate synthase. Among various schedules of administration, the efficacy of the Mayo Clinic bolus regimen, in which the two drugs are injected daily for five days every four weeks, has been validated in randomized trials
3
–
5
and is frequently used as first-line therapy for metastatic colorectal cancer.
Irinotecan (Camptosar, . . .
Journal Article
Ataluren (PTC124) Induces Cystic Fibrosis Transmembrane Conductance Regulator Protein Expression and Activity in Children with Nonsense Mutation Cystic Fibrosis
by
Mogenet, Agnès
,
Sermet-Gaudelus, Isabelle
,
Hanssens, Laurence
in
Adolescent
,
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
,
Biological and medical sciences
2010
Nonsense (premature stop codon) mutations in mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis (CF) in approximately 10% of patients. Ataluren (PTC124) is an oral drug that permits ribosomes to readthrough premature stop codons in mRNA to produce functional protein.
To evaluate ataluren activity, safety, and pharmacokinetics in children with nonsense mutation CF.
Patients were assessed in two 28-day cycles, comprising 14 days on and 14 days off ataluren. Patients took ataluren three times per day (morning, midday, and evening) with randomization to the order of receiving a lower dose (4, 4, and 8 mg/kg) and a higher dose (10, 10, and 20 mg/kg) in the two cycles.
The study enrolled 30 patients (16 male and 14 female, ages 6 through 18 yr) with a nonsense mutation in at least one allele of the CFTR gene, a classical CF phenotype, and abnormal baseline nasal epithelial chloride transport. Ataluren induced a nasal chloride transport response (at least a -5-mV improvement) or hyperpolarization (value more electrically negative than -5 mV) in 50% and 47% of patients, respectively, with more hyperpolarizations at the higher dose. Improvements were seen in seven of nine nonsense mutation genotypes represented. Ataluren significantly increased the proportion of nasal epithelial cells expressing apical full-length CFTR protein. Adverse events and laboratory abnormalities were infrequent and usually mild. Ataluren pharmacokinetics were similar to those in adults.
In children with nonsense mutation CF, ataluren can induce functional CFTR production and is well tolerated.
Journal Article
Longitudinal Evaluation of Working Memory in Duchenne Muscular Dystrophy
by
Elfring, Gary L.
,
Thangarajh, Mathula
,
Trifillis, Panayiota
in
Brain research
,
Clinical medicine
,
Clinical trials
2020
Objective: The developmental maturation of forward and backward digit spans—indices of working memory—in boys with nonsense (nm) Duchenne muscular dystrophy (DMD) (nmDMD) was assessed using prospective, longitudinal data. Methods: Fifty-five boys of the 57 subjects with genetically confirmed nmDMD—who were from the placebo arm of a 48-week-long phase 2b clinical trial—were evaluated. Forward and backward digit spans were obtained every 12 weeks for a total of five assessments in all study subjects. Changes in forward and backward digit spans were evaluated based on age, corticosteroid treatment, and DMD mutation location. Results: Boys with nmDMD had lower mean scores on normalized forward digit span. Normalized forward digit spans were comparable between subjects stratified by age and between corticosteroid-naïve and corticosteroid-treated subjects. When stratified by DMD mutation location, normalized forward digit spans were lower in nmDMD subjects with mutations downstream of DMD exon 30, exon 45, and exon 63, both at baseline evaluation and at follow-up evaluation at 48 weeks. On average, normalized backward digit span scores were stable over 48 weeks in these subjects. Developmental growth modeling showed that subjects with nmDMD mutations upstream of DMD exon 30, upstream of DMD exon 45, and upstream of DMD exon 63 appeared to make better gains in working memory than subjects with mutations downstream of DMD exon 30, downstream of DMD exon 45, and downstream of DMD exon 63. Conclusion: Performance in working memory shows deficits in nmDMD and differed based on nmDMD location. Maturation in cognition was seen over a 48-week period. The developmental trajectory of working memory in this cohort was influenced by DMD mutation location.
Journal Article
Surface viscosity and Marangoni stresses at surfactant laden interfaces
by
Elfring, Gwynn J.
,
Squires, Todd M.
,
Leal, L. Gary
in
Fluid mechanics
,
Interfaces
,
Surfactants
2016
We calculate here the force on a probe at a viscous, compressible interface, laden with soluble surfactant that equilibrates on a finite time scale. The motion of the probe through the interface drives variations in the surfactant concentration at the interface that in turn leads to a Marangoni flow that contributes to the force on the probe. We demonstrate that the Marangoni force on the probe depends non-trivially on the surface shear and dilatational viscosities of the interface indicating the difficulty in extracting these material properties from force measurements at compressible interfaces.
Journal Article
Ataluren use in patients with nonsense mutation Duchenne muscular dystrophy: patient demographics and characteristics from the STRIDE Registry
by
Elfring, Gary
,
Trifillis, Panayiota
,
Zhang, Olivia
in
ataluren
,
Clinical Medicine
,
Clinical trials
2019
Strategic Targeting of Registries and International Database of Excellence (STRIDE) is an ongoing, multicenter registry providing real-world evidence regarding ataluren use in patients with nonsense mutation Duchenne muscular dystrophy (DMD) in clinical practice (NCT02369731). Here, we describe the initial demographic characteristics of the registry population.
Patients will be followed up from enrollment for ≥5 years or until study withdrawal.
As of 9 July 2018, 213 DMD boys were enrolled from 11 countries. Mean (standard deviation) ages at first symptoms and at study treatment start were 2.7 (1.7) years and 9.8 (3.7) years, respectively. Corticosteroids were used by 190 patients (89.2%) before data cut-off. Mean (standard deviation) ataluren exposure was 639.0 (362.9) days. Six patients withdrew. STRIDE is the first drug registry for patients with DMD and represents the largest real-world registry of patients with nmDMD to date.
Journal Article